1. Field of the Invention
The present invention relates to a pulsed laser oscillator provided with an electrooptical element that polarizes light according to an applied voltage, and to a method of controlling pulsed laser oscillation. More specifically, the present invention relates to a pulsed laser oscillator that changes over time a voltage applied to an electrooptical element, so that a pulse width of laser light can be increased and peak energy of the output pulsed laser light can be decreased, and to a method of controlling pulsed laser oscillation.
2. Description of Related Art
Conventionally, there has been a pulsed laser oscillator that includes a laser medium, a light source for exciting the laser medium, and a resonator allowing light which has been emitted from the laser medium to reciprocate and to be amplified, to obtain pulsed laser light, in which a Q-switching element and a cavity dump element are located in the resonator in which a high-reflectance mirror is located at one side of the laser medium and a low-reflectance mirror is located at the other side thereof, to allow Q-switching oscillation to occur in a state in which the laser light is completely confined in the resonator, followed by operating the cavity dump element to cause cavity dumping near a peak level of the pulsed laser light accumulated in the resonator, so that energy accumulated in the resonator can be immediately drawn out (see, for example, Japanese Laid-open Patent Application Publication No. 2003-69118 A).
However, in such a conventional pulsed laser oscillator, since the energy accumulated in the resonator is immediately drawn out, the peak energy of the output pulsed laser light becomes too large, and thus, an object to be irradiated by the laser might be damaged.